Ordinary book making systems are essentially discontinuous processes. Books are prepared by printing the requisite numbers of each signature of the book separately. There is thus made a batch of a given number of a first signature which is then stored in a stack or on a pallet or the like and then the preparation of a batch of an equal number of a second signature is carried out, the batch of second signatures is then stored, and so on. When the time came for binding, one of each signature is taken in turn from the respective stored batches so that a set of signatures is arrived at and the set is bound together. This is clearly an uneconomical process involving much storage and handling and several propsals have been made whereby some of the worst disadvantages of the process could be overcome.
In U.S. Pat. specification No. 2631845 for example, the inventor shows how from a single web he may in a single operation produce four different signatures which are taken to four different delivery stations from his machine. He has thus streamlined the above-mentioned process in that in a single printing operation he produces a multiple number of signatures, but he still has to separately store them and then re-collate them later in sets for binding. Thus, this is not a continuous process since it is interrupted at the stage when the signatures have been produced and must then be stored or otherwise handled before being collated for binding.
In U.S. Pat. specification No. 2613077 there is disclosed a genuinely in-line or continuous process wherein dissimilar signatures are printed sequentially on a web of paper which is then folded and cut into signatures and the successively different signatures are then fed one after the other into pockets in a reception conveyor so that each pocket contains a set of signatures making up the whole book. These sets having been gathered up in the pockets are then deposited on a delivery conveyor which takes them away. This disclosure also discusses the possibility of signatures in this process being formed by "former-folding" i.e. the method of operation in which the spine fold of the signature is parallel to the longitudinal direction of the web from which the signature was formed rather than transverse to the longitudinal direction as in ordinary folding.
However, the conveyor pocket arrangement here is such that it is impossible to use this machine for the continuous printing of books which are to be bound "come and go".
Another attempt has been made to provide a continuous printing process and this is shown in United Kingdom Pat. No. 1215194. Here however the solution was in effect to print the whole book at once by means of a greatly elongate printing plate in the form of a belt. While this has advantages in some particular applications, there is a serious lack of adaptability in the sense that the only printing process which can be used is one which is available to that flexible belt, in that the machine as disclosed is inherently restricted to printing a single web, and is not adaptable to two-on printing for the purpose of "come and go" binding.
"Come and go" binding is per se known and there is an explanation of one form of it in the said U.S. Pat. No. 2631845 with particular reference to FIGS. 5 to 11. The process involves preparing pairs of similar signatures produced from a printing plate arranged so that it prints two distinct parts of a book on different sides of a longitudinal dividing line of the signatures and set in opposite directions. Then, for binding, the pairs of signatures (or pairs of batches of signatures) are placed face to face and bound together. They are then cut half way along their major edges and the product is two complete books. The advantages of this mode of working is to permit a doubled output per unit time from the binder and less production time lost in setting up the press without however using duplicate plates. However, the process has never yet been made continuous.
Nor would the continuous processes of the prior art discussed above be adapted to "come and go" binding at least without total duplication of all the parts of the machine up to the final deliverey conveyor, something which is completely uneconomic and unrealistic, not only from the point of view of duplication of the machinery involved but also from the point of view of double plate-making since identical sets of signatures will have to be prepared in all of the parts of these supposed machines.